2x² + 4x - 16 = 0
2(x²) + 2(2x) - 2(8) = 0
<u>2(x² + 2x - 8)</u> = <u>0</u>
2 2
x² + 2x - 8 = 0
x = <u>-(2) ± √((2)² - 4(1)(-8))</u>
2(1)
x = <u>-2 ± √(4 + 32)</u>
2
x = <u>-2 ± √(36)
</u> 2<u>
</u> x = <u>-2 ± 6
</u> 2<u>
</u> x = -1 ± 3
x = -1 + 3 U x = -1 - 3
x = 2 x = -4
<u />
Answer:
C :She is incorrect because she should have squared each leg length and then found the sum
The dimensions of the can are 1.457 inches and 2.913 inches that will give the most volume
Step-by-step explanation:
Let us revise the rule of surface area and volume of a cylinder
- S.A = 2π r h + 2π r²
- V = π r² h
Forty square inches of material is available to make a cylindrical; can of tuna and water, we need to find the dimensions of the can that will give the most volume
∵ S.A = 40 inches²
∵ S.A = 2π r h + 2π r²
∴ 2π r h + 2π r² = 40
Let us use this rule to find h in terms of r
- Subtract 2π r² from both sides
∵ 2π r h = 40 - 2 π r²
- Divide both sides by 2π r
∴ 
∴ 
∴ 
∵ V = π r² h
- Substitute h by its value above
∴ 
∴ V = 20 r - π r³
To find the most volume differentiate it with respect to r and equate it by 0 to find the value of r
∵
= 20 - 3π r²
∵
= 0
∴ 20 - 3π r² = 0
- Add 3π r² to both sides
∴ 20 = 3π r²
- Divide both sides by 3π
∴ r² = 2.122
- Take √ for both sides
∴ r = 1.457 inches
To find h substitute the value of r in the expression of h
∵ 
∴ 
∴ h = 2.913 inches
The dimensions of the can are 1.457 inches and 2.913 inches that will give the most volume
Learn more:
You can learn more about volume of solids in brainly.com/question/6443737
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